It is no great secret that transportation systems in major metropolitan areas are impossibly congested, and that the rising cost of operating urban mass-transit systems is straining the finances of many cities and states to the breaking point. In virtually all large American cities excessive use of private automobiles has resulted in dangerous levels of air pollution, unacceptably high consumption of imported oil, and an intolerable rate of personal injury and property losses due to accidents. The capacity of a typical highway lane is only 1,500 to 2,000 passenger cars per hour; as a result it is impossible to obtain enough land in urban areas to permit construction of freeways with sufficient numbers of lanes to alleviate congestion. Furthermore, even if such freeways were built, the existing network of city streets could not absorb the traffic flow that would result, and air pollution levels would be driven even higher. As a result, no transportation system based on the gasoline-powered private automobile is capable of solving urban transportation problems.
Electrically powered automobiles have not, to date, presented a viable solution to the foregoing problems. Electrically powered vehicles are handicapped by limited range, high cost, and inconvenience of use due to long recharging times. Even if these problems were overcome, congestion would not be relieved by the mere substitution of electric vehicles for gasoline-powered vehicles on our present highway system, nor would the rate of automobile accidents be reduced.
Steel-wheel-on-rail mass-transit systems suffer from a variety of handicaps, most of which result from the inherent limitations of this nineteenth century technology. The capacity of a single track is no greater than that of a single highway lane; higher capacities are achieved in present urban transit systems only by subjecting passengers to barbaric levels of overcrowding and discomfort. The typical urban rail system is slow; for distances of only several miles, travel times (including waiting time for trains) often exceed half an hour. Maintenance and operating costs for urban rail systems are high and rising; their reliance on mechanical, rail-moving switching systems is a proven safety hazard. Worst of all, passengers using urban rail systems "can't get there from here" as many destinations of choice are not within walking distance of stations. This inconvenience of use is one of the major factors which influences the potential ridership of urban mass-transit to rely on private automobiles instead.
Mass-transit systems based on buses suffer similar problems. Buses which use congested city streets are extremely slow. Buses which achieve higher speed, for example by operating on dedicated freeway lanes for high occupancy vehicles, lack the private automobile's capability to provide convenient on-demand departure to destination transport for individual riders.
Aircraft have not proved viable for short-distance mass-transit in urban and suburban areas.
Magnetically levitated (maglev) transportation systems appear greatly superior to other forms of transportation for inter-city travel over distances between approximately 50 and 500 miles. However, maglev systems cannot meet the needs of shorter distance travel within metropolitan areas. Although maglev can operate along most interstate highway rights of way at speeds of 300 miles per hour or greater, curvature and grades on likely urban rights of way, as well as noise considerations, limit peak urban-area speeds to the vicinity of 150 miles per hour. At such low speeds magnetic levitation is inefficient and uneconomical due to the effects of electromagnetic drag. Furthermore, maglev systems permit stations to be located no closer than 10 to 20 miles apart. Although this separation distance permits maglev systems to serve adjacent cities and metropolitan areas along a several hundred mile corridor, and represents one of maglev's great advantages over high-speed steel-wheel on rail technologies (which require much greater station separations), it is inadequate for service within urban areas.